1 Field of the Invention
The present invention relates to a magnetic disk drive which magnetically reads and writes data, and more particularly to a reading/writing device which reads from and writes data onto a magnetic data recording medium of a magnetic disk.
2 Related Art
FIG. 4 shows a prior art magnetic disk drive of this kind. In the FIG. 1 denotes a magnetic disk, 2 denotes the magnetic disk drive, and 3 denotes a reading/writing head device which is incorporated so as to read from and write magnetic data onto the magnetic disk 1. As shown in the figure, in the magnetic disk 1, a disk-like magnetic data recording medium (not shown) is rotatably incorporated in a pair of upper and lower shells 4 which are bonded to each other. A window 5 is formed in each of the shells 4 so that magnetic data recording surfaces 7 of the magnetic data recording medium 6 are partly exposed with a predetermined width in the sector direction and the whole width in the track direction. The windows 5 are opened and closed by slidingly moving a shutter 8 which is disposed so as to be slidable along end faces of the shells. An opening/closing lever device 9 for opening and closing the shutter 8 is disposed in the magnetic disk drive 2.
The opening/closing lever device 9 is placed in an upper side portion of the inner space of the magnetic disk drive 2. The lever device is disposed so that, when the magnetic disk 1 is inserted through a slot 11 of a disk holder 10, an input end 13 of a lever 12 abuts against the leading end faces of the shells 4 in the insertion direction, and also that, in accordance with the insertion of the magnetic disk 1, the input end 13 of the lever 12 is moved from the outer side in the width direction toward the inner side along the leading end faces of the shells 4 in the insertion direction. When the input end 13 of the lever 12 abuts against one end face of the shutter 8 in the width direction, the opening operation of the shutter 8 is started, and, when the magnetic disk 1 is completely housed in the disk holder 10, the shutter 8 is held to a fully opened state. In order to perform reading and writing of data on the magnetic data recording medium 6, a movable member 15 is disposed on a chassis 14 of the magnetic disk drive 2 so as to be movable back and forth. An upper carrier 17 is supported via a plate spring 16 on an upper portion of the tip end face of the movable member 15, and a lower carrier 18 is disposed on a lower portion of the tip end face so as to be opposed to the upper carrier 17.
Reading/writing heads 19 which read and write magnetic data are respectively fixed to leading end portions of the opposed faces of the upper and lower carriages 17 and 18 so as to be opposed to each other. The upper carrier 17 is integrally provided with support arms 20 which are outwardly projected from the right and left sides, respectively. A head-loading arm 21 disposed on the disk holder 10 supports one of the support arms 20 from the lower side. The upper carrier 17 is lowered from a disk insertion/ejection position which is relatively higher, to a read/write position which is relatively lower, by lowering the disk holder 10. At this time, the elastic force of the plate spring 16 causes the reading/writing heads 19 to be respectively contacted with the magnetic data recording surfaces 7 of the magnetic data recording medium 6 by a predetermined load pressure. In the disk holder 10, a cutaway portion 22 is formed by removing portions of faces which are opposed to the upper and lower carriages 17 and 18. The head-loading arm 21 is placed in the vicinity of the cutaway portion 22.
FIG. 5 is a side view of the disk drive 2. A cam plate 24 which is used for raising and lowering the disk holder 10 is interposed between the lower face of the disk holder 10 and the upper face 23 of the chassis 14, so as to be movable back and forth. Support shafts 28 which are outward protruded from the right and left sides of the disk holder 10 are vertically guided by flanges 26 and cam grooves 27 that are disposed on the cam plate 24, thereby raising and lowering the disk holder. The flanges 26 of the cam plate 24 are set to have a height which, when the support shafts 28 are supported on the upper end faces of the flanges, allows the disk holder 10 to be located at the disk insertion/ejection position. Each of the cam grooves 27 elongates obliquely downward toward the rear side of the chassis 14, and one end of the groove is opened in the upper end face of the corresponding one of the flanges 26 of the disk holder 10. The positions of the support shafts 28 and the cam grooves 27 are set so that the support shafts 28 are engaged from the rear side of the chassis 14 with the open ends of the cam grooves 27 and vertically moved along the cam grooves 27. The lifts of the cam grooves 27 are set so as to correspond to the elevating stroke of the disk holder 10. As a result, the disk holder 10 can be switched between the disk insertion/ejection position and the disk read/write position by a reciprocal movement of the cam plate 24.
In the magnetic disk drive 2 of the prior art, the magnetic disk 1 can be set to the read/write position by simply inserting the magnetic disk 1 into the disk holder 10 and then pushing the disk by a predetermined distance.
When the support arms 20 for raising and lowering the upper carrier 17 are formed by resin molding or the like so as to be outwardly projected, resonance occurs depending on the shapes, weights, and the like of the upper carrier 17 and the support arms 20. Alternatively, a method may be employed in which the upper carrier 17 is formed as a metal pressed product or a resin molded product, and the support arms 20 are formed as independent parts and then attached to the upper carrier 17. In the alternative, since the support arms 20 are formed as independent parts and the upper carrier 17 is formed into a complex shape by press-working or resin molding, a problem is caused in that the production costs is increased.
Consequently, there arises a technical problem which is to be solved in order to configure a magnetic disk drive of a simple structure and suppress resonance. It is an object of the invention to solve the technical problem.
The invention has been conducted in order to attain the object.
The invention provides a magnetic disk drive in which upper and lower carriages are elastically supported on a movable member that is moved back and forth by an actuator, to be vertically opposed to each other, and
a pair of upper and lower reading/writing heads are respectively disposed on opposed faces of the upper and lower carriages, the heads being respectively contacted from upper and lower sides with magnetic data recording surfaces of a magnetic data recording medium by a predetermined load pressure, to read and write data, wherein
projections are respectively disposed on the opposed faces of the pair of upper and lower carriages, to be opposed to each other,
slopes of a rising gradient and a falling gradient are formed in a space which is between the pair of upper and lower carriages and behind the projections, the slopes respectively allowing, when the movable member is separated from a zero track position of the magnetic data recording medium to be further moved toward a radial outside, the upper projection to be obliquely upward moved in a sliding manner, and the lower projection to be obliquely downward moved in a sliding manner, and
the pair of upper and lower reading/writing heads are respectively separated from the magnetic data recording surfaces by overriding of the projections over the slopes and sliding movements of the projections.
Furthermore, the invention provides a magnetic disk drive in which, in each of the rising-gradient slope, the falling-gradient slope, and the projections, hardness of at least a surface is set not to be lower than a predetermined value, for mutual sliding movement.